1. Field of the Invention
The present invention relates to a cold water tank and a water treatment apparatus having the same.
2. Description of the Related Art
Cold water tanks refer to devices, which are connected to or include cooling units to cool the water introduced therein, and drain the cooled water out of the tanks.
Referring to FIGS. 1A and 1B, a cold water tank may include a tank body 20 receiving and storing water, a water inlet pipe 30 provided at the tank body 20 to convey water into the tank body 20, and a water outlet pipe 40 provided at the tank body 20 to convey the water out of the tank body 20, and having an air vent hole 41 formed in its upper portion.
The water inlet pipe 30, as shown in FIGS. 1A and 1B, has its one end placed in the upper portion of the tank body 20, thereby facilitating water inflow into the tank body 20. The water outlet pipe 40 has its one end placed in the lower portion of the tank body 20, and this allows users to be provided with the water existing in the lower portion of the tank body 20 at a relatively low temperature. As depicted in the drawings, a refrigerant pipe 60 as a cooling unit is wound around the circumference of the tank body 20 to cool the water in the tank body 20. That is, the water, having flowed in the tank body 20 through the water inlet pipe 30, is cooled by heat exchange with a refrigerant flowing in the refrigerant pipe 60. The water cooled in the above manner is discharged out of the tank body 20 through the water outlet pipe 40.
While water is flowing into the tank body 20 through the water inlet pipe 30, as shown in FIG. 1A, the air within the tank body 20 passes through the air vent hole 41 in the upper portion of the water outlet pipe 40 and exits out of the tank body 20 through the water outlet pipe 40. As shown in FIG. 1B, if the tank body 20 is completely filled with water, all of the air in the tank body 20 exits through the water outlet pipe 40 via the air vent hole 41. If, in this state, the water in the lower portion of the tank body 20 is discharged through the water outlet pipe 40 to supply cooled water to a user, then the water in the upper portion of the tank body 20 undesirably passes through the air vent hole 41 and drains through the water outlet pipe 40.
As described above, the water existing in the upper portion of the tank body 20 may be different in temperature from the water existing in the lower portion of the tank body 20. That is, the water in the upper portion of the tank body 20 has a higher temperature than the water in the lower portion of the tank body 20.
Accordingly, as described with reference to FIG. 1B, in the event that the water in the upper portion of the tank body 20 passes through the air vent hole 41 and drains through the water outlet pipe 40, the water in the upper portion and the water in the lower portion, having different temperatures, may mix undesirably in the water outlet pipe 40. That is, the water existing in the upper portion of the tank body 20 at a relatively high temperature may be supplied, mixed with the water existing in the lower portion of the tank body 20 at a relatively low temperature. This may result in the supply of water having a higher temperature than desired.
The above limitations may also be caused in water treatment apparatuses including the cold water tank 10, such as water purifiers or water ionizers.